package com.applets.framework.shiro.web.session;

import com.applets.common.utils.Threads;
import org.apache.shiro.session.mgt.DefaultSessionManager;
import org.apache.shiro.session.mgt.SessionValidationScheduler;
import org.apache.shiro.session.mgt.ValidatingSessionManager;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Lazy;
import org.springframework.stereotype.Component;

import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

/**
 * 自定义任务调度器完成
 *
 * @author LufeiClimb
 */
@Component
public class SpringSessionValidationScheduler implements SessionValidationScheduler {
    public static final long DEFAULT_SESSION_VALIDATION_INTERVAL =
            DefaultSessionManager.DEFAULT_SESSION_VALIDATION_INTERVAL;
    private static final Logger log =
            LoggerFactory.getLogger(SpringSessionValidationScheduler.class);
    /** 定时器，用于处理超时的挂起请求，也用于连接断开时的重连。 */
    @Autowired
    @Qualifier("scheduledExecutorService")
    private ScheduledExecutorService executorService;

    private volatile boolean enabled = false;

    /** 会话验证管理器 */
    @Autowired
    @Qualifier("sessionManager")
    @Lazy
    private ValidatingSessionManager sessionManager;

    // 相隔多久检查一次session的有效性，单位毫秒，默认就是10分钟
    @Value("${shiro.session.validationInterval}")
    private long sessionValidationInterval;

    @Override
    public boolean isEnabled() {
        return this.enabled;
    }

    /**
     * Specifies how frequently (in milliseconds) this Scheduler will call the {@link
     * org.apache.shiro.session.mgt.ValidatingSessionManager#validateSessions()
     * ValidatingSessionManager#validateSessions()} method.
     *
     * <p>Unless this method is called, the default value is {@link
     * #DEFAULT_SESSION_VALIDATION_INTERVAL}.
     *
     * @param sessionValidationInterval
     */
    public void setSessionValidationInterval(long sessionValidationInterval) {
        this.sessionValidationInterval = sessionValidationInterval;
    }

    /** Starts session validation by creating a spring PeriodicTrigger. */
    @Override
    public void enableSessionValidation() {

        enabled = true;

        if (log.isDebugEnabled()) {
            log.debug(
                    "Scheduling session validation job using Spring Scheduler with "
                            + "session validation interval of ["
                            + sessionValidationInterval
                            + "]ms...");
        }

        try {
            executorService.scheduleAtFixedRate(
                    new Runnable() {
                        @Override
                        public void run() {
                            if (enabled) {
                                sessionManager.validateSessions();
                            }
                        }
                    },
                    1000,
                    sessionValidationInterval * 60 * 1000,
                    TimeUnit.MILLISECONDS);

            this.enabled = true;

            if (log.isDebugEnabled()) {
                log.debug("Session validation job successfully scheduled with Spring Scheduler.");
            }

        } catch (Exception e) {
            if (log.isErrorEnabled()) {
                log.error(
                        "Error starting the Spring Scheduler session validation job.  Session validation may not occur.",
                        e);
            }
        }
    }

    @Override
    public void disableSessionValidation() {
        if (log.isDebugEnabled()) {
            log.debug("Stopping Spring Scheduler session validation job...");
        }

        if (this.enabled) {
            Threads.shutdownAndAwaitTermination(executorService);
        }
        this.enabled = false;
    }
}
